Electroplated receptacle



May 9, 1944. A G, K, @KRAFT 4 2,348,549

Filed April 6,- 1945 www . handle as a separate piece thickness only amounting Patented May'9, 1944 g OFFICE ELECTROPLATED RECEPTACLE George Konstantin Pontns Kraft,

' Stockholm, Sweden Application April 6, :1943, Serial No.

In Sweden December 12, 1940 1 claim. (ci. zzn-so] The present invention relates to an improvement in receptacles made ofv electrically nonconducting vitreous materials, such as glass, porcelain,A stoneware,

one piece with the receptacle. More specifically theinvention relates to household articles of the speciiied typesuch as teapots, Jugs, soup-basins and the like, which are'provided with an outer metallic covering for protective and esthetic purposes. 'I'he object of the invention is to eiect a suillcient heat insulation between the receptacle proper and its handle. in spite of the fact that the whole outer metallic shell which covers receptacle and handle is made in to prevent the handle from assuming an excessive temperature when the receptacle contains a hot liquid.

It is previously known to this kind with an electrolytically deposited metallic coating in order 'to protect the brittle maferial from breakage due to rough handling or accidents. The electrolytic deposition of such a protective metallic shell on the surface of the brittle material entails several advantages, since `already a metal coating with a thickness of about 0.5 mm. (l/.toinch) will provide a very efficient protection and, furthermore, may be polished, engraved or decorated so as to present a very attractive surface, giving to the receptacle the appearance of being entirely of metal, 'while preserving the sanitary and other advantages of porcelain, glass, etc. that are desirable for teapots` and similar receptacles for hot beverages.

Household articles of this kind, particularly coil'ee and teapots and the like, have, in spite of these advantages, only received a. limited use because of the fact that the metallized handle soon becomes too hot to be conveniently grasped by the unprotected hand when the receptacle is illed with a hot liquid. It has been attempted to prevent this heat transport by making the jointed to the receptacle proper with an insulating insertion. Quite apart'from the fact that such arrangements are etc.,l and having one or i several handlesdirectly attached to or made in one piece; so as provide containers of l .cient thickness of 5:1. The employment expensive and mechanicallyunsatisfactory, they have proven ineffective in all those cases. where the outer metallic shell is made in one continuous piece, covering receptacle 'and handle without l presenting any joints or other discontinuities, which for esthetic as well as practical reasons is the desired form.

This heat transport from receptacle to handle, which in the case of unmetalliae'd porcelain and glass objects, is generally not perceptible to any such degree that it causes any inconvenience. has thus in the hitherto known metal protected articles of the kind described, been of such magnltude, even in the case of metal coatings with a to a small fraction of means.

the reason for this I have, however, discovered strong heat transport and accumulation in the handle, which has enabledV me i to devise the way or providing sumcient heat insulation between receptacle and handle while still maintaining'the continuous metallicshell,

' and with the receptacle and handle made in one piece without any insulating insertions between the same. v y When electrolytically producing metal coverings oi' suilicient thickness to lailorcl thedesired protection ci' the underlying brittle non-conductive material, it is for technical reasons always necessary to'employ 'such metals in the deposit which possess high electric conductivity, particularly copper, in more special cases silver or gold. Layers of these metals may alternate with layers of metals with lower conductivity, e. g., Fe, Nl. Cr, Cd, Zn or their stitute the chief material of the deposit in order to make it possible to-obtain a covering of sumand elasticity. `According to known electroplating'processes the surface of the electrically non-conducting object is iirst rendered conductive by applying thereto a thin coating of gold. graphite'or several lays of i'or instance alternately nickel and copper `may then be deposited by electrolytic It is possible by electroplating means to produce dense and well adhering copper deposits oi 4practicallyV any desired thickness even on strongly curved surfaces such as receptacles of the .kind in question, thanks to the electroplating properties of copper baths, whereas/less conductive metals. e. g., Fe, Ni, Cr, Cd, Zn, etc., can only be deposited in comparatively thin layers to avoid brittleness, spong'lness. poor adhesion or other detrimental properties in the deposit. In general the ratio of thickness of each copper layer to the other metal layers is of the order of magnitude of comparativelythlck layers of copper is preferable not only for electroplating reasons but also because oi' the fact that copper is ductible and malleable, which makes it 'capable of otlering better protection' for the underlying brittle porcelain or glass material against blows and hits than most other metals which are electroplated onto the object. Whether copper is used alone or in alternate layers with, e. g..

nickel, an outermost layer of chromium, gold, silver-or other omamenting or non-corroding metal is generally plated onto the underlying sheet of base metal. A suitable arrangement is to plate a thin layer of. nickel on copper and to provide the nickel with a coating of chromium by known electroplating methods. 'y

My invention can be explained in more detail by reference to the accompanying drawing which alloys,'but must always con-V the like, on which one or A shows, more orless diagrammaticaiiy, an illuscoatings in accordance with this invention.

trative embodiment of a tea pot having metallIic' this showing'. g

Fig. 1 is an elevation of the tea pot, while Fig. 2`is an enlarged partial elevational view of the area outlined by the dotted lines in Fig. l, the view being partly in vertical section, taken through the handle and body of the tea pot, showing the metal layers thereon. This iigure is provided with legends showing the diilerent metal layers and it will be noted that a layer of copper is provided on the bocly of ythe receptacle only, while both body and handle are coated with continuous layers of nickel and chromium. The copper layer is absent from the-handle, this absence causing the handle to remain cool when the receptacle is lled with a hot liquid. r

As already mentioned, such protective and ornamental electrodeposits of metals on household articles of vitreous materials, such as glass, porcelain, etc., whichare provided withone or several handles, have proven of little value due to the fact that the handle very soon assumes an excessive temperature lwhen lthe receptacle is filled with a hot beverage.

ceptacles made of metal throughout, has naturally been attributed to the knownheat-conducting properties of metals in general. My systematic researches, however, have led to the surprising discovery that the presence of electrically highly conducting metals, e. g., copper, in the metal coating is'the source of this unwanted heat-transfer from receptacle to handle. If, namely, in the covering` on the handle only such metals are employed which have a lower conductivity, such as nickel and chromium, the heat transfer will become reduced to such a degree that the handle will remain about as cold as an unplated porcelain handle.- The discovery of this surprising and singular phenomenon at once presented the way to overcome the above discussed disadvantages.

Owing to the shape which the handle in general possesses, it has proven possible to electroplate the same without any difilculty solely with the above Ametals having low electric conductivity. According to the 'invention a highly conductive metal, e. g., copper, is thus used only in the covering on the receptacle proper, whereas the handle orhandles are wholly, or in more yspecial cases at least for a certain distance near the zone of transition between handle and receptacle, proy metallic material. The other metals are, on the.

other hand, plated as nearly uniformly over receptacle and handle as possible so as to'form a coherent outer covering -over the entire object comprising receptacle proper and handle. Sumcient mechanical protection is in general obtained for the handle by this arrangement but,.if desired, `the total deposit .of copper, on the handle may be made heavier by This fact, which i places such receptacles in the same class as 'reexpedients well known to any person skilled' in the art of electroplating to make up for the missing layer of copper.

No other explanatio of this surprising heatconducting effect than the considerable diiIerence in regard to heat'conductivity of on the one hand copper and similar electrically high-conducting metals and low-conducting metals, has so lfar been found. Even considering the fact that copper is an about 3 to 4 times better heat conductor than for'instance nickel' or chromium, it is still highly surprising that a layer of copper in the metal-covering, with a thickness only a few'tenths of a millimeter, will exercise such a marked influence on the heat transport.' Tests carried out onV two perfectly similar receptacles (ordinary coffee pots of porcelain with handle in one piece therewith of the same material) plated with a base of copper on nickel with a continuous covering j of chromlum.on nickel over the whole object of equal thickness and with perfectly identical appearance, the only diierence `being that the copper layer in the deposit was one pot whereas it missing on the,handle of formed a coherent stratum in the deposit covering the entire -other pot, gave as result that in the latter case it was impossible to grasp the handie of the pot without burning the hand after having lled the pot with a hot iluid, while the handle on the other pot under the same circumstances remained practically as cool as an unplated porcelain handle. Further tests have demonstrated that it is without practical importance if the copper layer is close to the porcelain or deposited as an intermediate layer, for instance between two layers of nickel. The heateven appear in cases where a thickness considerably below 0.1 m'm. In all these cases the heat eiect in the handle will bepractically the same, whereas it is actively eliminated when copper (or other conducting effect will the copper layer has highly Aconductive metal) is missing in the covering on the handle.

A very thin coating of a. highly conducting metal such as gold or silver, which may sometimes be desirous the form of a continuous or fretted top layer on the outside of household objects of this kind will, owing to its extreme thinness (order of magnitude one hundredths millimeter), not have the same eiect as the stratum of copper in the metal covering proper, for which reason such a. thin ornamenting deposit on the outer surface may be used without detrimental effect.

I claimzV A receptacle having an handle of vitreous material integral body and a forv holding hot liquids,

' said body-only being -providedwithan electrometals, other than deposited protective coating of copper while said body. andhandleare covered with an electrodeposlted coating of at least one metal selected from the group consisting of nickel and chro- 'xnium,A at least the'outermost of theselayers forming a coherent'continuous covering of metal for the outer surface of said body and handle: the absence of copper in the coveringon' the handle causing said handle to remain cool when a hot liquid is placed in said receptacle.

GEORGE KoNs'rANTIN PoN'rUs on the other hand electrically' both of which were electrofor ornamental purposes in 

